This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A197277 #7 Jun 02 2025 04:49:20 %S A197277 9,67,317,2731,16890,114205,886737,6017949,40918349,290053910, %T A197277 2074566978,14599100959,101671464178,714232555115,5052846176923, %U A197277 35608078988237,249861298059545,1755724243450685,12370064599008231,87120870560445460 %N A197277 Number of nX5 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 2,0,1,1,1 for x=0,1,2,3,4. %C A197277 Every 0 is next to 0 2's, every 1 is next to 1 0's, every 2 is next to 2 1's, every 3 is next to 3 1's, every 4 is next to 4 1's %C A197277 Column 5 of A197280 %H A197277 R. H. Hardin, <a href="/A197277/b197277.txt">Table of n, a(n) for n = 1..210</a> %e A197277 Some solutions containing all values 0 to 4 for n=4 %e A197277 ..1..0..0..1..2....1..1..0..1..2....0..1..3..1..1....1..0..1..1..0 %e A197277 ..2..1..1..4..1....0..1..1..4..1....1..4..1..0..0....1..0..1..4..1 %e A197277 ..2..1..4..1..0....1..1..4..1..0....3..1..3..1..1....1..0..3..1..3 %e A197277 ..1..0..1..3..1....1..0..1..3..1....1..0..0..1..2....2..1..1..0..1 %K A197277 nonn %O A197277 1,1 %A A197277 _R. H. Hardin_ Oct 12 2011